An analytical model for the forecasting of the Blue Nile River low flow is developed and compared with the current modified similar year method. The model is based on the general non-linear reservoir equation and the historical flow of the river for the calibration period 1912-1961. The comparison is made after the year 1961 for 6 different years in terms of the temporal 10-day flows and for the period 1962-1996 in terms of the standard error of estimates (SEE). The model and the modified similar year forecasted 10-day flows were also compared with the actual temporal 10-day flows during the driest and the wettest year of the whole record between 1912-1998. Results showed that the model temporal distribution of flows is more close to the actual ones compared with the modified similar year method. The model has less SEE in 31 years out of 38 compared with the modified similar year method.